Abstract
The development of techniques for studying sex chromatin from oral mucosa (Moore and Barr, 1955; Marberger at al., 1955), and chromosomes from peripheral blood (Moorhead et al., 1960), has made it possible to undertake population surveys to identify individuals with abnormal sex chromosomes. The present knowledge of psychiatric effects of the sex chromosome abnormalities has been derived mainly from comparing their frequency in the psychiatric population with that in the general population.